A tenor guitar is a fretted four stringed instrument, most commonly shaped like a guitar, sometimes smaller than a normal guitar, which usually has a scale length of 23 inches and which is tuned in "fifths" to CGDA. It has been around for 100 years or more, built by some of the most famous companies and played by several well-known musicians in a wide variety of musical styles.

Although it is now quite hard to pinpoint when the very first tenor guitar was built, and very early models seem to be quite rare, Gruhn and Carter, in their superb book 'Guitars and Other Acoustic Instruments - A Photographic History' state that one of the major instrument manufacturers at the latter part of the nineteenth century, 'Lyon and Healy', whose main guitar brand name was 'Washburn', claimed to have invented the tenor guitar just after the turn of the twentieth century. Certainly tenor guitars must have been around in the latter part of the first decade of the twentieth century from the existence of published and dated instructional books for both the tenor guitar and tenor banjo from this period that still exist today.

The mandolin family of instruments had been immensely popular in the latter part of the nineteenth century, at the turn of the century and well into the first decade of the twentieth century. However, the popularity of the tenor banjo (or 'tango banjo', as it was sometimes called) significantly began to overshadow that of the mandolin family towards the end of the second decade of the twentieth century.

This was happening because the tenor banjo was particularly suited to be used as the main rhythm instrument in the new style of exciting music played by small groups that the world would soon come to know as 'jass' or 'jazz'. The tenor banjo's sharp and cutting sonority, partly derived from its tuning in fifths, compared to that of the more mellow six string guitar, was particularly suited to the newly emerging, but still primitive, technology of acoustically recording this type of music onto acetate or metal discs which were then used as moulds for pressing the familiar black discs.

It is not surprising, therefore, that some of the earliest tenor guitars were also built by banjo manufacturing companies which they could possibly have seen initially as a way to expand their markets, and then eventually maintain their markets. Two of the major guitar manufacturers of the twenties that still exist today, Martin and Gibson, along with some other banjo manufacturers of the period, started to manufacture tenor guitars in significant numbers towards the end of the 1920s. In the case of Martin and Gibson this was in 1927, and it is undoubtedly linked to the beginnings of a trend away from the banjo, as the main rhythm instrument in jazz bands and dance orchestras, and towards the guitar, whether four or six string.

The tenor guitar is tuned exactly like a tenor banjo, and one of the major roles of the tenor guitar has been to allow tenor banjo players, and possibly mandolin family players, because of their similar tunings, to instantly double on the guitar without having to learn the scales and chord shapes for the entirely different tuning of a six string guitar.

In music there is the diatonic scale, or "do re mi fa so la ti do". In musical letters this scale would be "C D E F G A B C". It is an eight note scale where the first note and eighth note are one octave apart. If you start with the first note, C, and count up five notes (C d e f G) you arrive at G. If you start at G and count up five notes (G a b c D) you arrive at D. If you then start at D and count up five notes (D e f g A) you finally arrive at A.

The tenor guitar (and the tenor banjo) are thus tuned CGDA which is in "fifths", where the C is the note one octave below middle C and the A is referenced as an A440 because it has a frequency of 440 Hertz (Hz) where 1 Hz is one cycle per second.

Because it is tuned in fifths, chord voicings are much more spread out than they are on a 6 string guitar. This is why if a "C" chord played on the six string and a "C" chord played on the four string tenor guitar, the tenor guitar "C" will sound much more 'open'.

It is also possible to tune a tenor banjo or guitar to another tuning in fifths using GDAE. This type of tuning is commonly associated with Irish music and the tuning is used because it involves playing with fiddles and mandolins, instruments that are also tuned to GDAE. The use of this tuning, however, is not restricted to this style of music.

The tuning in fifths also means that the tenor guitar, and it's cousin the tenor banjo, are similar to the violin and mandolin families of instruments, mandolin, violin, mandola, viola, mando-cello and cello, and they can all be played with the same chord shapes.

The violin, viola and cello all have four strings each, whereas mandolin family instruments have eight strings in four pairs or 'courses' that are each tuned to the same note, usually in unison but sometimes an octave apart, similar to what is seen in the tuning of the various pairs of strings on the twelve string guitar, the two highest of which are unison and the four lower of which are octaves apart.

A mandolin, like a violin, is tuned to the highest pitch, to GDAE, a mandola, like a viola, is tuned lower to CGDA, (which is exactly the same tuning as the tenor banjo and guitar) and a cello, like a mando-cello, is also tuned to CGDA but exactly one octave below the mandola CGDA tuning. This means that tenor banjo/guitar, mandola and mando-cello can all be played using the same scales and chord shapes.

One transitional instrument also tuned CGDA and closely related to the development of the tenor guitar is the tenor lute, a wooden instrument with a teardrop shaped body and a tenor banjo neck. They were made by several manufacturers, including Lyon and Healy, Paramount and Gibson, who brought out their model in 1924. It was not a successful instrument and not many were made, although examples can still be seen. Paramount also made what was essentially a banjo with a wooden body and called it a 'tenor harp'.

Another very important type of transitional instrument of this period of the late twenties and early thirties were the metal bodied resonator tenor and plectrum guitars made by National and Dobro. Although they were somewhat guitar-like in sound and their resonator systems gave them significant volume, they also had a very unusual sonority and many tenor or plectrum banjo players doubled on these instruments to add variety and character to their playing in jazz and other types of bands of the period such as 'western swing' or 'Texas swing' and Hawaiian bands.

The plectrum banjo was another popular instrument that was used for the rhythm sections of jazz bands and dance orchestras, particularly on the West Coast of the U.S.A. It was generally tuned C or D, G, B,D which, like the tenor banjo, gave rise to another type of four string guitar, tuned in a similar way, which was called a plectrum guitar. Unlike the tenor guitar though, he plectrum guitar had a scale length of 26 inches, making it closer to that of a normal six string guitar.

Like tenor banjo players, plectrum banjo players took up the plectrum guitar, as the banjo waned in popularity in the late twenties and early thirties, and the most notable jazz musician to do this was Eddie Condon who stayed with this Gibson L7 four string plectrum guitar all his life. The longer scale length of the plectrum banjo or guitar also made it easier for this type of instrument to be tuned DGBE like the top four strings of a six string guitar. The plectrum guitar, however, was generally never produced in very large numbers and nowadays is considered to be quite a rarity, although National plectrum guitars are more common.

The tenor guitar can be considered to be a transition instrument between Dixieland banjo and the six string swing guitar, particularly as it started to outpace the tenor banjo in popularity, towards end of the 1920s. This trend quickened when important players of the period like Eddie Lang and Carl Kress, switched from banjo to six string guitars. Clearly though the tenor guitar has a distinctive sound and style of its own, and there is literally no limit to the many styles of music that can be made from this unique instrument which can be heard in country music, western swing, and jazz, as well as contemporary folk and pop music.

As the six string became more standard, in later years some musicians acquired tenor guitars and would string them up and tune them like the top four strings on a six string guitar, DGBE. They were playing tenor guitars, but they were not playing them in true tenor tuning. One of the most notable jazz guitarists to do this was Tiny Grimes who was strongly influenced by the six string jazz guitar pioneer, Charlie Christian. Tiny played his electric four string tenor guitar in this style right through from the forties until the seventies when his musical career ended.

Nick Reynolds, of the Kingston Trio, played a Martin 0-18T tenor guitar. The C.F. Martin Company has recently released a special 25th anniversary edition of the instruments used by the Kingston Trio - a Vega long neck five string banjo, a Martin Dreadnought six string guitar and this tenor guitar. Many people bought tenor guitars after seeing Nick Reynolds play it with that famous folk group.

Today, the tenor guitar is also finding a place in contemporary folk and pop music, as well as Celtic and other ethnic styles. Among the contemporary players, Ani di Franco plays a tenor guitar on a few of her songs, using various tunings that include one (ADAD) based on GDAE that through the root D and the fifth note of the D scale A, makes a partial open D chord, comparable to the 'DADGAD' open D tuning on a six string guitar used for slide playing

At one time most of the major banjo and guitar manufacturers, including Gibson, Gretsch, Martin, National, Dobro, Harmony, Regal, Paramount, Vega and Epiphone, produced a line of tenor guitars including acoustic, electric, metal or wood resonator, flat top and archtop models. Today tenor guitars are built by only a handful of private luthiers.

While most people have a reasonable idea of what ukuleles, mandolins, banjos or guitars are, the "tenor" guitar remains much less well known, and an often misunderstood musical mystery. It is hoped that this introduction has provided some useful enlightenment about it.